A map of areas where chikungunya is known to exist. (World Health Organization)

World Health Organization

“The affected St. Martin residents had not traveled recently, suggesting that chikungunya virus is now present in island populations of mosquitoes and is being spread locally. Further spread on St. Martin, to other Caribbean islands, and to the surrounding mainland areas is possible in the coming months and years. The mosquitoes that spread it are also found in some areas of the United States,” the CDC said in a statement on its website.

The virus causes “abrupt onset” of fever and severe joint pain, similar to arthritis, but some people may also experience muscle pain, nausea, headaches, rash or fatigue.

“The joint pain is often very debilitating, but usually ends within a few days or weeks,” the World Health Organization (WHO) said on its website.

WHO said chikungunya patients generally recover in full, usually in about a week, and treatment is focused on the relief of symptoms.

But, some people may suffer long-term joint pain as a result of becoming infected. The CDC said it is rarely fatal.

The CDC notice is only a “Level 1” or watch, meaning travellers should “practice usual precautions.”

That includes using mosquito repellent and wearing long-sleeved shirts or long pants at times when mosquitoes are prone to bite — early morning and late afternoon/evening.

Silviane John, director of the St. Martin Tourist Office, told The Associated Press both sides of the island are cooperating closely to reduce mosquito breeding sites and increase public awareness about the importance of dumping out stagnant water. Mosquito fogging trucks are frequently seen on the streets, she said.

“It’s a concern for us right now, for sure. We haven’t heard of any cancellations from hotels or airlines so it is a wait-and-see game,” John said from St. Martin, where many of the visitors are French as well as Americans or Canadians escaping from the northern cold.

St. Martin’s government was drafting a letter to airlines letting them know how they are battling the spread of the virus, John said.

The island is already battling an outbreak of dengue fever commonly spread by the Aedes aegypti mosquito, which also spreads chikungunya, The Associated Press reported.

The CDC said it has been preparing for the arrival of the virus in the region since 2006 and created guidelines, with the assistance of the Pan American Health Organization (PAHO), in 2011.

The CDC has in the past documented cases of chikungunya in the U.S., but all were in travellers.